This invention relates to internal shoe drum brakes, and more specifically to mechanism for automatically adjusting the clearance of the brake shoes from the brake drum to compensate for brake shoe wear.
The use of automatic brake adjusters in conjunction with drum brakes is well-known, as is exemplified by U.S. Pat. Nos. 4,276,966 and 4,401,195. In the interest of saving weight in automotive vehicles in order to gain improved fuel economy, wheels and brakes have been made smaller. That is, their diameter has been reduced. As a result, brakes with a 7.08 inch (180 mm) diameter drum are being used in some vehicles. Such a small diameter drum leaves insufficient room between the brake wheel cylinder and the wheel bearing hub for the type of automatic brake adjusters used previously.
I have invented a brake adjuster which fits in the available space in brakes with 7.08 inch (180 mm) diameter drums and still provides enough linkage movement so that the brake shoe clearance can be adjusted back to the minimum clearance when the brake shoe clearance reaches the maximum design clearance.